Spiral girder



Patented Mar. 13, 188s.

W. W'. GREEN.

SPIRAL GIRDER.

(No Model.)

UNITED STATES PATENT OFFICE.

WILLIAM WAREN GREEN,

OF CHICAGO, ILLINOIS.

SPIRAL GIRDER.

SPECIFICATION forming part of Letters Patent No. 379.217. dated March13, 1888. Application filed September 22, 1886. Renewed August 1l. 18N.Serial No. 246,682. (No model. l

To aZZ whom it may concern:

Be it known that I, WILLIAM WAREN GREEN, of Chicago, Illinois, haveinvented a new and useful Spiral Gir-der, of which the following is afull, clear, and accurate description.

My invention relates to a novel manner of constructing a spiral girder,in which a spiral or hoop of metal is used to hold in position thevarious braces and tension rods or cables composing the spiral girder. Iattain this object by the mechanism illustrated in the accompanyingdrawings, in Which- Figure l is a side elevation of the spiral girder.Fig. 2 shows in parta longitudinal section through the tension andcompression rods or pipes of the girder. Fig. 3 shows an end elevationof the brace-plates between which the spiral is confined.

Similar letters of reference indicate corresponding parts throughout theseveral views.

A are the breast-plates, between which the spiral of girder is confined.

Bis aspiral, composed of iron, and is instrumental in keeping thetension and comprese sion rods or pipes through which the whole strainof the girder is taken at their respective distances apart.

C are rods or cables extending the entire length of the girder, and bindthe girder together.

D are the compression rods or pipes th rough which the compressionstrain ofgirder is taken.

E is a guy rod or cable, and is secured tothe breast-plates A at eachend, the middle part oi' said guy-rod passing underneath the spiral ofgirder.

rl`he spiral B is secured to the breast-plates A by the rods or cables Cand nuts c, the said rods or cables taking into the said breastplates.The cables or rods C pass through the metal of spiral, and are securedat each end to the breast-plates A by nuts e.

Each individual compression rod or pipe D equals in length the 'distancebetween the suecessive helical surfaces of the spiral, and each continuous line of said compression pipes acts as one undivided length. Acable C, passing through the center of each individual compression-pipe,forms each of the said lines of compression-pipes into one, so that eachof the said continuous lines acts as one incor-V porate whole.

The guy-rod E is of importance in certain cases that the girder may beplaced in, notably when the girder is supported at each end. Vhen thegirder is supported at the middle, such guy-rod is of no service; or,.if used, it should be placed diametrically opposite, or on the top sideof girder.

The guy-rod E, of which there may be several, sustains a similar strainas the tensionrods C ofthe gir-der, and also acts as a diagonal brace.

The spiral girder is applicable in all cases of ordinary girders, andthe same form of girder is suitable to be used for masts of' vessels,lighthouses, or wherever a vertical column requires to be erected toagreat vertical height.

Having thus described my invention, what I claim as new and original,land desire to secure by Letters Patent, is as follows:

1. rPhe combination, in a spiral gil-der, of the spiral B, extendingfrom and connecting with the breastplates A, the tension rods or cablesC, passing through each successive helix of the spiral B and connectingwith 'the breast-plates A, and the compression pipes or rods D, whichreach from helix to helix of spiral B, substantially as shown anddescribed.

2. The combination, in a spiral girder, With the guy rods or cables E,extending from breastplate to breast plate of the spiral P, andcoinpression-pipes D, reaching from helix to helix of spiral, ot therods or cables C, secured to the breast-plates A by nuts c,substantially as shown and described.

WILLIAM WAREN GREEN.

Vitnesses:

WM. H. Ross, E. D. GREEN.`

